ARM: 5621/1: at91/dmaengine: integration of at_hdmac driver in at91sam9g45 series

This is the integration of DMA engine driver into at91sam9g45 series
device file.
The associated driver is at_hdmac.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>